This invention relates to sidewall coring tools used to obtain samples of the formation through which a borehole is drilled. In determining the physical properties of subterranean formations, it is of great assistance to have samples of the formation which are commonly called cores. A core is typically a cylindrical piece of the rock which has been cut from the underground formation that can vary in size and length. A typical size is 1/2 inch in diameter and 4 to 6 inches long although samples can be of larger diameters and of greater length depending on the facilities available. One type of core cutter is the type to be used to cut the cores from the sidewall of a borehole after the borehole has already been drilled. Such a sidewall coring tool is described in U.S. Pat. No. 4,354,558 entitled "Apparatus and Method for Drilling into the Sidewall of a Drill Hole," issued Oct. 19, 1982, Alfred H. Jageler, Robert A. Broding, Lauren G. Kilmer, inventors. This invention relates to such a sidewall coring tool.